1. Field of the Invention
The present invention relates to a recall circuit for quitting a power saving mode and, more particularly, to a recall circuit for quitting the power saving mode of a television or an LCD monitor.
2. Description of Related Art
As shown in FIG. 1, a prior power saving device disconnects I2C pins that communicate with other chips 30, via a bi-channel analog mixer and a segregator 50, to attain the power saving mode. To shift the power saving mode to a normal mode, a video signal collecting chip 40 is required for detecting and communicating. At the shift moment, the other chips 30 are turned off, so the voltage levels of the I2C pins are uncertain. When the system is shifted from the power saving mode to the normal mode, it is required to have the video signal collecting chip 40 and microprocessor 11 to restore the communication with the other chips 30. However, the voltage level of I2C pins of the microprocessor 11 at the moment would be reduced by the uncertain voltage level of I2C pins of the other chips 30 to a low level, causing unavailability of normal communication with other chips, further causing unavailability of the screen and resulting in trouble of use.
Another technique of the prior art uses the bi-channel analog mixer and segregator 50 to control the communication between the microprocessor 11 and the other chips 30 to make the voltage levels of microprocessor 11 and I2C pins of the video signal collecting chip 40 not to be influenced. However, this method still requires the use of the bi-channel analog mixer and segregator 50 to control the voltage level of I2C pins so it is unable to solve the said problem perfectly and will still cause trouble to the users.
Therefore, it is desirable to provide an improved recall circuit for quitting a power saving mode to mitigate and/or obviate the aforementioned problems.